Is this a customers car? I've found that sometimes the paint will peel off those hoods if you dont sand that primer off and reprime with some good stuff.it might take a few months,if its your car you'll know what to do if it happens.

No, this is my daily driver. I hate to part with it although it has extremely high mileage (230k) because it gets such great gas mileage. All it really needs is a halfway decent paint job and I will be happy with it.

Well thats differnt,Try getting up underneath the paint with a razor blade and then useing a blower to blow the paint off.see what happens,if it all blows right off pretty ez we'll know something for sure...Cut the tops (peaks) of the wrinkle and get underneath from there

I've had this problem before and I know what etching primer is... What I'm saying is ....This works,I've done it...I also dont take chances I'll test out an idea before tring it out on a car. If I say it works its not just some crazy thought,It works and I've acually done it.

I understand that you would know what it is. I am just saying from a technical standpoint, and that is usually the answer to most questions, "etching primer" is meant for bare metal, PERIOD.

The fact is because something "works" when initially done means nothing.

You could paint two coats of lacquer paint over bare metal on the hood of your work truck that sits in the the weather all day long. It would "work" for many months, and then it would come off in sheets revealing a rusted hood.

The concept of an acid etching primer being sprayed over ANYTHING makes sense in that it is etching the surface. And on that plastic bumper, it makes sense that it would do just that.

But at the same time, is it doing the same thing as it is on bare metal as it is designed? The acid flashes off with the solvents when it is applied, that is how it works. Would it flash off when sprayed over something like plastic or "bondo" when that plastic or "bondo" is absorbing the solvents more than a bare metal would? I would imagine not, that the plastic is "sucking" in some of the solvent and acid. What happens if it isn't flashed off once something is applied over it?

READ THE TECH SHEETS is all I can say. The manufacturer isn't stupid, the R&D dept lay out instructions to ensure that the product is used in the best possible way. The way that makes it work the best. Anything but bare metal is not in the list of "suitable substrates" in the tech sheet for etch primer.

Just because a mason chesel is made to break blocks dosent mean it wont work perfectly for straightining out body lines.I used etching primer on hundreds of those cheap bumpers some didnt even have primer at all It was standerd proceedure at my shop,my own painter didnt believe it till he tried it....Problem solved... it was reading the ingrediants that made me realize it might work.not the instructions...but i found it was cheaper in the long run to use a better quality bumper since they'll shatter when bumped not bend.I've personaly replaced no less than 500 of these bumpers probably more like 1000... It works.but there are other ways... playing it safe is always recomended like i said before ,especialy of the inexperanced or if someone else is buying the materials...this is just another option to think about. I watch every dollar going out of my shop so cost is always factor. doing things twice is not an option...

Wow, been awhile, huh? Well, I got the car finished up in Oct but I forgot to post pics. I decided to let the bumpers go because the weather was getting cold and my schedule was picking up, but I plan on finishing them sometime within the next 2 weeks. The paint job is not perfect by any means, I would do some things differently the next time around, but the car looks 10x better now than it did, so I am content.

Bent 2 rims right after I took those pics, ended up getting inexpensive new ones and new tires.

Anyway, thanks a lot for all of your help, it really came in handy before and during the project. I am going to try to get the bumpers done in the next 2 weeks so hopefully I will have some "final" pictures soon.

I think your problem is the cheap 1k primer is still on there. it will wrinkle when solvents from the 2k primer get trapped . keep putting the lacquer thinner on it until no more black comes off.. try a red scuff pad soaked in thinner...that cheap primer gives us fits.

I thought it was the problem too, but I had already taken the primer completely off of the front bumper, and the rear bumper was the factory bumper which I sanded down and it had several spots with wrinkling paint.

I will try to get them finished in the next week or two and I will see what happens I guess.

When Ford was building Mustangs in the Old San Jose factory (now a shopping Mall) They used a streetsweeper-scrubber to clean the aisles in the factory. One day about 6 cars in a row all came out with wrinkled paint, A few days it happened again. It turned out the guy running the street sweeper was pouring a very active solvent in with the soap to get the grease spots off the floor. Every time he drove down the aisle next to the paint oven air intakes the fumes from the wet floor would cause wrinkling. That solvent was locked in a cabinet with restrictions where and who could use it.

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